What Do Festive Cracker Jokes Do to Our Minds?

"How much did Father Christmas's sleigh cost? Nothing, it was on the house."

This quip is met by groans that echo through a warehouse in London.

We're at a joke-testing meeting with a firm that makes products for social events. Its catalogue includes festive crackers.

The firm's founder smiles, almost sheepishly at the gag. But the pun has made the cut and will appear in upcoming crackers.

"You measure the joke by the number of groans and the intensity of the groans around the table," the founder says.

The secret to a great Christmas cracker joke is not the identical as a good joke per se. It is all about the context - in this case, the shared laughter of the Christmas dinner table with elders, kids and possibly neighbours.

"The goal is for the gag to be a thing that brings the eight-year-old in harmony with the grandparent," she states.

The Neuroscience Of Shared Laughter

Coming together to experience shared laughter is not only nothing new, scientists say, it is probably to be older than humanity.

"Therefore when you are laughing with others at the Christmas dinner you are engaging in what's almost certainly a really ancient mammal social vocalisation," says a professor.

Shared laughter, she says, helps make and maintain social bonds between individuals.

Scientists have found that a absence of these interactions can seriously damage mental and physical health.

"Those you converse with, and share laughter with, it leads to increased levels of 'happy chemical' release," the professor continues.

These natural chemicals are the body's "feel-good compounds" and are released both to reduce tension and discomfort and in reaction to enjoyable experiences, such as laughing with friends over a truly terrible festive cracker joke.

"It's not simply laughing at a foolish joke with a holiday cracker," the expert states. "You are actually doing a lot of the really important task of building, preserving the social bonds you have with the people you love."

Which Happens Inside the Brain?

But what is actually happening inside the brain when we hear a gag?

An awful lot occurs in response to humour, it transpires.

Employing brain scanning technology, a type of brain scanner which indicates which parts of the mind are more active, scientists have been able to chart the regions that receive more blood.

Testing entails scanning the minds of volunteer participants and then subjecting them to a collection of funny phrases, paired with either a neutral sound, or pre-recorded chuckles.

"In the scanner we observed a very interesting activation pattern of neural activity," says the professor.

A joke stimulates not just the areas of the brain in charge of auditory processing and interpreting speech, but also brain areas involved in both planning and initiating movement and those involved in vision and memory.

Combine all of this together, and people hearing a pun have a sophisticated series of brain responses that support the amusement we experience.

The Infectious Power of Chuckles

Scientists discovered that when a humorous word is combined with laughter there is a stronger response in the brain than the same phrase when followed by a non-emotional sound.

"This was in areas of the brain that you would employ to move your face into a smile or a chuckle," she explains.

It means we are not just responding to funny words, they are reacting to the laughter that accompanies them.

Laughter, says the professor, can be infectious.

So what does this imply for the chuckles found around a Christmas table?

"People laugh harder when you know others," she says, "and laughter increases further when you are fond of them or care for them."

When it comes to Christmas cracker puns, she says, the feel-good factor is more probable to be caused not by the gag itself, but from the reaction to it.

"The laughter is key. The gag is the dreadful Christmas cracker pun, and it's just a reason to laugh together."

The Quest for the Perfect Festive Pun

Is it possible to find the ultimate joke?

Likely not, but that has not stopped researchers from attempting to.

Years ago, a psychologist established a scientific search for the planet's funniest gag.

More than tens of thousands of jokes later, with scores lodged by 350,000 participants around the world, he has a better idea than most as to what works and what does not.

The perfect festive cracker pun needs to be short, he says.

"But they also need to be poor jokes, jokes that make us moan," he continues.

The increasingly "terrible" the joke, he states the more effective.

"This is because if nobody finds it funny – it's the joke's fault, not yours.

"What's interesting about the holiday cracker puns is that none of us considers them funny.

"It creates a common moment around the gathering and I think it's wonderful."